package dragon.core.util;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

@SuppressWarnings("serial")
public class VerificationCode extends HttpServlet {

	private static final Logger logger = LoggerFactory.getLogger(VerificationCode.class);

	/**
	 * @param request
	 *            HttpServletRequest
	 * @param response
	 *            HttpServletResponse
	 * @throws ServletException
	 * @throws IOException
	 */
	protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		response.setContentType("image/jpeg");
		response.setHeader("Pragma", "No-cache");
		response.setHeader("Cache-Control", "no-cache");
		response.setDateHeader("Expires", 0);
		HttpSession session = request.getSession();
		// 在内存中创建图象
		int width = 42, height = 17;
		BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
		// 获取图形上下文
		Graphics g = image.getGraphics();
		// 生成随机类
		Random random = new Random();
		// 设定背景色
		g.setColor(getRandColor(200, 250));
		g.fillRect(0, 0, width, height);
		// 设定字体
		g.setFont(new Font("Times New Roman", Font.BOLD, 16));
		// 画边框
		// g.setColor(new Color());
		// g.drawRect(0,0,width-1,height-1);
		// 随机产生120条干扰线，使图象中的认证码不易被其它程序探测到
		g.setColor(getRandColor(160, 200));
		for (int i = 0; i < 120; i++) {
			int x = random.nextInt(width);
			int y = random.nextInt(height);
			int xl = random.nextInt(12);
			int yl = random.nextInt(12);
			g.drawLine(x, y, x + xl, y + yl);
		}
		// 取随机产生的认证码(4位数字)
		// String rand = request.getParameter("rand");
		// rand = rand.substring(0,rand.indexOf("."));
		// String sRand="";//原来的设置代码
		char[] rands = generateVerificationCode();
		// for (int i=0;i<4;i++){
		// String rand=String.valueOf(random.nextInt(10));//原来的设置代码
		// sRand+=rand;//原来的设置代码
		// 将认证码显示到图象中
		g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));// 调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
		// g.drawString(rand,9*i+2+2,12);////原来的设置代码

		g.drawString("" + rands[0], 9 * 0 + 2 + 2, 14);
		g.drawString("" + rands[1], 9 * 1 + 2 + 2, 14);
		g.drawString("" + rands[2], 9 * 2 + 2 + 2, 14);
		g.drawString("" + rands[3], 9 * 3 + 2 + 2, 14);
		// }
		// 将认证码存入SESSION
		// session.setAttribute("rand",sRand);//原来的代码
		session.setAttribute(GlobalParameter.VerificationCodeSessionKey, new String(rands));

		// 图象生效
		g.dispose();
		ServletOutputStream responseOutputStream = response.getOutputStream();// first
		// none
		// 输出图象到页面
		ByteArrayOutputStream bos = new ByteArrayOutputStream();
		// ImageIO.write(image, "JPEG", response.getOutputStream());//原来的设置代码
		ImageIO.write(image, "JPEG", bos);
		// 以下关闭输入流！first none
		byte[] buf = bos.toByteArray();
		response.setContentLength(buf.length);
		responseOutputStream.write(buf);
		bos.close();
		responseOutputStream.close();
		// responseOutputStream.flush();//原来的设置代码
		// responseOutputStream.close();//原来的设置代码
	}

	Color getRandColor(int fc, int bc) {// 给定范围获得随机颜色
		Random random = new Random();
		if (fc > 255) {
			fc = 255;
		}
		if (bc > 255) {
			bc = 255;
		}
		int r = fc + random.nextInt(bc - fc);
		int g = fc + random.nextInt(bc - fc);
		int b = fc + random.nextInt(bc - fc);
		return new Color(r, g, b);
	}

	@Override
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doPost(request, response);
	}

	@Override
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		String action = request.getParameter("act");

		if (!StringUtils.isEmpty(action) && "verify".equals(action.trim())) {
			// 校验
			String code = request.getParameter("code");
			String flag = "";
			if (StringUtils.isEmpty(code)) {
				flag = "f";
			} else {
				code = code.trim().toLowerCase();
				flag = code.equals(request.getSession().getAttribute(GlobalParameter.VerificationCodeSessionKey)) ? "t" : "f";
			}
			response.setCharacterEncoding("UTF-8");
			try {
				response.getWriter().println(flag);
			} catch (IOException e) {
				logger.error(e.getMessage(), e);
			}
		} else {
			// 刷新
			processRequest(request, response);
		}
	}

	private char[] generateVerificationCode() {
		String chars = "23456789abcdefghijkmnpqrstuvwxyz";// 取消了有疵议的0,0以及1,l
		char[] rands = new char[4];
		for (int i = 0; i < 4; i++) {
			int rand = (int) (Math.random() * chars.length());
			rands[i] = chars.charAt(rand);
		}
		return rands;
	}
}
